Trinome, by Bilotti
I first borrowed one of these from mandolinist Chris Thile, who got it from an old music teacher of his. This box operates on 120V, 60Hz AC. The electricity causes the main axle to rotate at a constant speed. A speed lever (on the right) engages speeds ranging from 19 to 29 revolutions per minute based on different sizes of cogs. The three beat levers (bell, tick, tock) engage beats numbered 1 to 8, singly or in combination. You multiply the RPM-lever by the beat-engage-lever to get the beats per minute (BPM). At up to three beat divisions at a time, the Trinome is a great tool for polyrhythm study. Combine this with the drone box and you’ll likely never leave your house.